Dibenzylidene sorbitol (also called dibenzaldehyde monosorbitol acetal, or dibenzyl monosorbitol acetal or dibenzylidene monosorbitol acetal) and derivatives thereof such as those which are substituted on one or both of the aromatic rings with a fluorine or methoxy group and those which have the sorbitol portion replaced with other reduced sugars such as xylitol or ribitol as described in U.S. Pat. No. 5,609,855 assigned to Procter & Gamble (collectively referred to as dibenzylidene sorbitol or "DBS") may be used in various food and cosmetic applications. For cosmetic uses the more interesting ones are those focused on obtaining a translucent or clear products. While dibenzylidene sorbitol is stable in alkaline or neutral media, such compounds are not stable in acidic media. In an acidic environment, such as in the presence of acidic antiperspirant materials, and when in the presence of even small amounts of water, the dibenzylidene sorbitol deteriorates and breaks down. Also, the use of DBS sometimes causes problems in the aesthetics of cosmetic products or problems with structural properties. Accordingly, there is a need to find a way to form products containing DBS which are stable and which have acceptable aesthetics.
There have been various attempts to work with DBS. Some of these efforts have focused on the stability of DBS. United Kingdom Patent GB 2 280 111, assigned to Union Camp Corporation, describes a gel stick composition comprising a dihydric alcohol as a primary solvent, a co-solvent such as low molecular weight polyethylene glycol, water and/or glycerine, a buffering agent and DBS as a gelling agent.
U.S. Pat. No. 4,720,381 to Schamper et al notes stability problems with this approach and itself describes the use of solvents having less reactive alcohol groups or alcohols with selected chain lengths in a DBS composition.
U.S. Pat. No. 4,816,261 to Luebbe et al describes stable deodorant gel stick compositions comprising DBS with a polar solvent and a coupling agent such as polypropylene glycol ethers of fatty alcohols.
U.S. Pat. No. 4,518,582 to Schamper, et al discloses an antiperspirant stick composition containing dibenzyl monosorbitol acetal in the presence of acidic antiperspirant-active salts, which composition is stable for extended periods of time at elevated temperatures. The composition contains at least a reactive solvent (such as water, methanol, ethanol, n-propanol, ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, etc.), dibenzyl monosorbitol acetal, an antiperspirant-active compound, and a gel stabilizer, the gel stabilizer such as magnesium sulfate, zinc acetate and hexamethylenetetramine and mixtures thereof. This patent discloses that the stabilizer prevents or retards deterioration of the gelled sticks, especially when exposed to elevated temperatures.
Another patent disclosing stabilizers for solid gel antiperspirant sticks containing an acidic antiperspirant-active compound in the presence of dibenzyl monosorbitol acetal is U.S. Pat. No. 4,719,102 to Randhawa, et al. This patent discloses that the sticks include a solvent which is a small, polar organic compound such as cyclic esters, amides, amines, ketones, ureas, carbamates, sulfoxides and sulfones, and their open chain analogs; a cosolvent such as primary or low molecular weight alcohols and/or glycols; dibenzyl monosorbitol acetal; an antiperspirant-active compound; and a gel stabilizer such as N-(2-hydroxyethyl) fatty (C.sub.8 -C.sub.20) acid amides, magnesium sulfate, zinc acetate, acetamide monoethanol amine and hexamethylenetetramine, and mixtures thereof.
U.S. Pat. No. 4,722,835 to Schamper, et al also discloses antiperspirant gel stick compositions gelled with dibenzyl monosorbitol acetal and containing an acidic antiperspirant compound, and also containing a stabilizer for the gel. This patent teaches that the compositions include a solvent which is a small, polar organic compound, as discussed previously in connection with U.S. Pat. No. 4,719,102; dibenzyl monosorbitol acetal; an antiperspirant-active compound; and a gel stabilizer such as (such as zinc oxide, calcium acetate, magnesium oxide, calcium carbonate, calcium hydroxide, magnesium carbonate, sodium carbonate, zinc carbonate and potassium carbonate). This patent discloses that these basic metallic salt gel stabilizers can stabilize the gel, even at high temperatures.
Other patent documents also disclose antiperspirant sticks gelled with a dibenzylidene sorbitol and include stabilizers for the gel.
EP Application No. 451,002 A2 discloses a stable, substantially anhydrous and substantially lower monohydric alcohol free, transparent, gelled, antiperspirant composition gelled by dibenzylidene monosorbitol acetal, containing acidic antiperspirants, and utilizing dihydric alcohols containing 3 to 6 carbon atoms as solvents, with the acetal being stabilized against hydrolysis and the formation of benzaldehyde by the presence of a stabilizing amount of a selected organic base, the organic base being a weakly basic, nitrogen-containing, organic compound.
EP Application No. 512,770 A1 discloses a stable, substantially anhydrous and substantially lower aliphatic monohydroxy alcohol free cosmetic composition gelled by dibenzylidene monosorbitol acetal, and containing acidic antiperspirant compounds and utilizing dihydroxy aliphatic alcohols containing 3-6 carbon atoms as solvents, wherein the dibenzylidene monosorbitol acetal gelling agent is stabilized against hydrolysis and the formation of benzaldehyde by the presence of a stabilizing amount of a selected inorganic base, the inorganic base including alkali and alkaline earth metal oxides, hydroxides, carbonates or bicarbonates, and trivalent metallic hydroxides.
PCT No. WO92/19221 discloses solid antiperspirant compositions in gel stick form, having an acid pH, and including (1) an antiperspirant active; (2) a gelling agent selected from the group consisting of substituted and unsubstituted dibenzylidene alditols; (3) a solvent for the gelling agent, preferably including a solvent material selected from the group consisting of monohydric and polyhydric alcohols, and mixtures thereof; and (4) a gelling agent stabilizer, the stabilizer being a basic metallic salt of an acid having a pKa of from about 3.8 to about 6.5 at 25 degrees C., the salt being at least partially soluble in the composition and being selected from the group consisting of C.sub.4 -C.sub.6) dicarboxylate salts, C.sub.6 -C.sub.8 monocarboxylate salts, and substituted or unsubstituted benzoate salts, and mixtures thereof, the gelling agent stabilizer not containing amino or amido functionalities. This patent document teaches that for clear or translucent sticks, the gelling agent stabilizer present in the composition should be fully soluble in the composition, in order to minimize refraction of light.
The foregoing patent documents also disclose methods for forming the disclosed antiperspirant stick compositions containing the antiperspirant materials and gelling agent. In particular, attention is directed to U.S. Pat. No. 4,719,102 and U.S. Pat. No. 4,722,835. Each of these patents discloses processes of forming the stick compositions, including dissolving the antiperspirant active in one phase and the dibenzyl monosorbitol acetal gellant in another phase. The two phases are then combined and poured into a mold or into the final package. The other components are added to either of the two phases depending on the compatibility of the component with the phases. More phases can be utilized, if desired, by forming a separate solution of some of the components, with the separate phases then being added to either of the two main phases; or all of the phases could be poured together at the end, as, for example, with a multi-stream filling head or an in-line mixer.
PCT No. WO92/19221 discloses a process of forming an antiperspirant gel stick, including preparing a solution containing the gelling agent, a solvent for the gelling agent, and the gelling agent stabilizer; mixing an antiperspirant active into such solution; and cooling the solution to form a gel.
There have also been efforts to develop DBS compositions to improve the aesthetics and/or mechanical properties while not sacrificing stability.
U.S. Pat. No. 4,346,097 to Roehl discloses a solid translucent gelled antiperspirant composition comprising DBS with an oleaginous compound (such as selected siloxanes, selected esters with an aliphatic character and branched chain hydrocarbons) to reduce stickiness.
PCT Publication Number 96/26709 to Vu et al describes a clear gel cosmetic stick which includes a liquid vehicle, an antiperspirant salt dissolved in the liquid vehicle, DBS and one or both of hydroxypropyl cellulose and a chelating agent. The hydroxypropyl cellulose maintains the hardness of the stick.
U.S. Pat. No. 4,863,721 to Beck et al describes the use of particulate cellulose ether polymers such as hydroxyethyl cellulose in antiperspirant compositions which are substantially free of polar solvents.
European Patent 0 260 030 B1 assigned to Unilever N. V. describes a transparent deodorant stick containing DBS and a thickening agent such as a chemically modified cellulose, polyacrylic acid, and/or polyacrylic acid copolymers and mixtures of the foregoing.
None of these references however, describes the use of guar such as a hydroxypropyl guar in connection with DBS and other components for a clear underarm product such as an antiperspirant stick. In particular it is noted that cellulose and guar are based on different carbohydrate building blocks that are arranged in a different way and, hence, give different properties in selected applications. Cellulose is water insoluble and gives plants the ability to maintain height. Cellulose is a linear polymer made of glucose units linked in a beta arrangement 1 to 4. Guar, on the other hand, is water soluble and is used to protect propagating plant seed. Guar is a branched polymer made from a linear backbone of mannose units linked in a beta arrangement 1 to 4 with random side chain attachments of galactose units linked to the mannose units in an alpha arrangement 1 to 6. Derivatives such as propylene glycol or butylene glycol ethers of either cellulose or guar would also reflect these structural differences.
Prior teachings of guar components in cosmetic applications include hair and or body care such as cleansing agents (see for example, U.S. Pat. No. 4,374,825 to Bolich et al; U.S. Pat. No. 4,556,510 to Holsopple; and U.S. Pat. No. 4,678,606 to Akhter et al.
While, as seen in the foregoing, there has been numerous efforts to find satisfactory cosmetic compositions suitable for use in forming underarm products such as deodorants and antiperspirants, for example, antiperspirant sticks, including clear antiperspirant gel sticks, containing acidic antiperspirant active ingredients and gelled with a dibenzylidene sorbitol, it is still desired to provide improved products, including, but not limited to, a clear stick composition containing an acidic antiperspirant active ingredient and gelled with dibenzylidene sorbitol and a selected guar which has increased stability over extended periods of times, and wherein deterioration of the gelling agent, and production of benzaldehyde due to such deterioration, are reduced. It is also still desired to provide an efficient manufacturing process for such cosmetic compositions.
It is a further object of the present invention to provide a clear antiperspirant and/or deodorant solid gel stick composition, which may contain an antiperspirant active salt and which is gelled by dibenzylidene sorbitol and a guar, the stick having structural integrity over extended periods of time (that is, to provide a rigid solid stick maintaining rigidity over extended periods of time).
It is a still further object of the present invention to provide a method of manufacturing clear antiperspirant solid gel stick compositions, utilizing dibenzylidene sorbitol and guar as a gelling system, wherein the processing for forming the stick is simplified.